Answer with speakerphone option?

After playing with the moto droid and doing a quick app search, I still don't know if there is a setting to answer the phone with speakerphone...as opposed to pressing the speakerphone button after answering the call.
I use Google Voice with call presentation and I keep missing the caller ID announcement because the screen blacks out after answering with the slider for a quick sec...maybe due to the proximity sensor?
But does anyone know of an app (or setting) to answer the phone by speakerphone directly?